1. Field of the Invention
The present invention relates to novel anti-ulcer agents chracterized by containing quassinoids as active ingredients and to novel quassinoids as the active ingredients thereof.
2. Prior Arts
Some of quassinoids which have antineoplastic actions have been found from some species of the Simaroubaceae plant. For example, quassin and neoquassin (also called as picrasmin) [Valenta et al., Tetrahedron Letters, 1960, 25; Tetrahedron, 18, 1433 (1962)] have been extracted from Quassia amara L. (=Surinam quassia) of the Simaroubaceae plant, whose origin is Brazil, Central America; and bruceantin [Kutney et al., Heterocycles, 3, 639 (1975); ibid., 4, 997 (1976); and ibid., 4, 1777 (1976)] from Brucea antidysenterica Mill. whose origin is Ethiopia. Further, ailanthone was extracted from Ailanthus altissima (Origin: Japan) [H. Naora et al., Chem. Letters, 661 (1982)] and eurycomanone from Eurycoma longifolia whose origin is Indonasia [Darise et al., Phytochem., 22, 1514 (1983)]. However, it has never been reported that anti-ulcer actions are recognized on those quassinoids.
Although a patent application disclosing that active ingredients of the Simaroubaceae plant, .beta.-carboline derivatives have an anti-ulcer action has been laied open (JPN Unexam. Pat. Pub. No. 60-58990), they are quite different from the compounds of the present invention in structure.